U.S. patent application number 14/130283 was filed with the patent office on 2014-12-25 for scandium extraction method.
The applicant listed for this patent is Kyushu University, National University Corporation, SUMITOMO METAL MINING CO.,LTD.. Invention is credited to Yuzo Baba, Masahiro Goto, Fukiko Kubota.
Application Number | 20140377150 14/130283 |
Document ID | / |
Family ID | 49160859 |
Filed Date | 2014-12-25 |
United States Patent
Application |
20140377150 |
Kind Code |
A1 |
Goto; Masahiro ; et
al. |
December 25, 2014 |
SCANDIUM EXTRACTION METHOD
Abstract
Provided is a method for selectively extracting and
inexpensively recovering scandium from an acidic solution
containing calcium, magnesium, and scandium. The scandium
extraction method according to the present invention involves
subjecting an acidic solution containing calcium, magnesium, and
scandium to solvent extraction using an extraction agent consisting
of an amide derivative represented by the general formula below. In
the formula, R.sup.1 and R.sup.2 represent the same or different
alkyl groups, and R.sup.3 is a hydrogen atom or alkyl group. The
amide derivative preferably consisting of one or more derivatives
selected from glycine amide derivatives, histidine amide
derivatives, lysine amide derivatives, and aspartic acid amide
derivatives. The pH of the acidic solution is preferably
pre-adjusted to between 1 and 4. ##STR00001##
Inventors: |
Goto; Masahiro;
(Fukuoka-shi, JP) ; Kubota; Fukiko; (Fukuoka-shi,
JP) ; Baba; Yuzo; (Fukuoka-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kyushu University, National University Corporation
SUMITOMO METAL MINING CO.,LTD. |
Fukuoka-shi, Fukuoka
Tokyo |
|
JP
JP |
|
|
Family ID: |
49160859 |
Appl. No.: |
14/130283 |
Filed: |
February 21, 2013 |
PCT Filed: |
February 21, 2013 |
PCT NO: |
PCT/JP2013/054419 |
371 Date: |
December 30, 2013 |
Current U.S.
Class: |
423/21.5 ;
562/561 |
Current CPC
Class: |
C22B 3/001 20130101;
Y02P 10/234 20151101; C07C 237/06 20130101; C22B 3/0005 20130101;
C22B 59/00 20130101; C22B 3/0024 20130101; C22B 3/0032 20130101;
Y02P 10/20 20151101 |
Class at
Publication: |
423/21.5 ;
562/561 |
International
Class: |
C07C 237/06 20060101
C07C237/06; C22B 59/00 20060101 C22B059/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 13, 2012 |
JP |
2012-056134 |
Claims
1-4. (canceled)
5. A scandium extraction agent consisting of an amide derivative
represented by the following general formula (1). ##STR00007##
6. The scandium extraction agent according to claim 5, wherein the
amide derivative is at least any one of a glycine amide derivative,
histidine amide derivative, lysine amide derivative and aspartic
acid amide derivative.
7. A scandium extraction method comprising: subjecting an acidic
solution containing calcium, magnesium and scandium to solvent
extraction by way of the scandium extraction agent according to
claim 5.
8. The scandium extraction method according to claim 7, wherein the
acidic solution is subjected to the solvent extraction while
adjusting the pH of the acidic solution to the range of 1 to 4.
9. The scandium extraction method according to claim 7, wherein the
acidic solution is a solution formed by mixing sulfuric acid with
nickel oxide ore to leach out nickel.
10. A scandium extraction method comprising: subjecting an acidic
solution containing calcium, magnesium and scandium to solvent
extraction by way of the scandium extraction agent according to
claim 6.
11. The scandium extraction method according to claim 8, wherein
the acidic solution is a solution formed by mixing sulfuric acid
with nickel oxide ore to leach out nickel.
Description
TECHNICAL FIELD
[0001] The present invention relates to a scandium extraction
method and, in detail, relates to a method of efficiently
separating and extracting scandium from an acidic solution
containing calcium, magnesium and scandium.
BACKGROUND ART
[0002] Scandium, which has the smallest atomic number among the
rare earth elements, has been used as a material for metal halide
lamps, an added element in alloys, an added element in catalyst
ceramics, and the like. However, scandium is expensive, the output
thereof is limited, and separation and refinement are difficult,
and thus the application of scandium has been limited.
[0003] However, nickel oxide ore such as laterite ore has been
known to contain very small amounts of scandium. The scandium
contained in nickel oxide ore can be recovered from the leachate
obtained by adding sulfuric acid to the nickel oxide ore and
pressurized extracting.
[0004] For example, Patent Document 1 shows that it is possible to
recover nickel and scandium from oxide ores by performing: (A) a
leaching step of leaching the oxide ore with an acid under high
temperature and high pressure to obtain a leachate containing
nickel and scandium; (B) a first neutralizing step of removing iron
and aluminum in the leachate as precipitates by adjusting the pH to
the range of 2 to 4 by adding a neutralizing agent to this
leachate; (C) a second neutralizing step of recovering scandium in
the solution as a precipitate by adjusting the pH to more than 4 to
7.5 by adding a neutralizing agent to the solution after removing
the precipitates in the first neutralizing step; and (D) a third
neutralizing step of recovering nickel in the solution as a
precipitate by adjusting the pH to more than 7.5 by further adding
neutralizing agent.
[0005] However, various problems arise when trying to industrially
operate with the method described in Patent Document 1. For
example, since the pH adjustment range in the first neutralizing
step and the pH adjustment range in the second neutralizing step
are adjacent, there is a possibility of scandium also precipitating
along with iron and aluminum in the first neutralizing step,
leading to an extraction rate decline for scandium, and there is a
possibility of iron and aluminum precipitating along with scandium
in the second neutralizing step, leading to a purity decline for
scandium, and neither are preferable. In addition, although large
amounts of precipitates are generated by adding a neutralizing
agent, in general, the characteristics of the precipitates obtained
by adding an alkali to an acid are unstable and poor in
filterability, and there is a possibility of being accompanied with
a cost increase such as the enlargement of the equipment scale. For
this reason, it is preferable to decrease the number of times of
the neutralizing step as much as possible, and it has been proposed
to selectively separate only scandium by a means such as solvent
extraction from a solution containing scandium.
[0006] Patent Document 2 shows that high purity scandium oxide is
obtained by extracting scandium component into organic solvent by
adding the organic solvent to an aqueous-phase scandium-containing
solution containing, in addition to scandium, at least one among
iron, aluminum, calcium, yttrium, manganese, chromium and
magnesium, then in order to separate trace components extracted
along with scandium in the organic solvent, scrubbing is performed
by adding a hydrochloric acid aqueous solution, and after removing
the trace components, the scandium remaining in the organic solvent
is made into a slurry containing as Sc(OH).sub.3 by adding a sodium
hydroxide aqueous solution to the organic solvent, the Sc(OH).sub.3
obtained by filtering this is dissolved with hydrochloric acid to
obtain a scandium chloride aqueous solution, and scandium oxalic
acid precipitate is formed by adding to this oxalic acid, the
precipitate is filtered, and after separating the trace impurities
in the filtrate, calcining.
[0007] However, in the case of employing the method of Patent
Document 2, not only scandium, but also impurity components are
extracted in the organic solvent to an extent that cannot be
ignored. Calcium, magnesium, etc. are abundantly present
particularly in the leachate obtained by acid leaching and
neutralizing nickel oxide ore, and for this reason, in addition to
the problem of labor and cost required in scrubbing, there is also
a further problem in the treatment of drainage generated
accompanying scrubbing.
[0008] In addition, Patent Document 3 discloses an extraction agent
called DODGAA, which has a diglycol amic acid backbone. According
to this extraction agent, the solubility in water is extremely
small, and as well as complete incineration being possible,
comparing with existing phosphorous-based compounds, it has
superior rare earth metal extractability and selective
separability, as well as the synthesis cost being low.
[0009] However, since scandium is very sensitive to pH, upon
extracting scandium even with the above-mentioned extraction agent
shown in Patent Document 3, a practical extraction rate is not
obtained if maintaining the pH at a constant or higher. Moreover,
in the pH range suited to the extraction of scandium, the
extraction rate of not only scandium, but also calcium and
magnesium increase, and thus it is difficult to selectively
separate only scandium.
[0010] [Patent Document 1] Japanese Unexamined Patent Application,
Publication No. 2000-313928
[0011] [Patent Document 2] Japanese Unexamined Patent Application,
Publication No. H9-291320
[0012] [Patent Document 3] Japanese Unexamined Patent Application,
Publication No. 2007-327085
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0013] The present invention aims to provide a method for
selectively extracting and inexpensively recovering scandium from
an acidic solution containing calcium, magnesium and scandium.
[0014] The present inventors have thoroughly researched to solve
the above-mentioned problems, and found that the above-mentioned
object can be achieved by solvent extracting using an extraction
agent consisting of an amide or an amide derivative, thereby
arriving at completion of the present invention.
Means for Solving the Problems
[0015] More specifically, the present invention provides the
following.
[0016] A first aspect of the present invention is a scandium
extraction method that includes: subjecting an acidic solution
containing calcium, magnesium and scandium to solvent extraction by
way of an extraction agent consisting of an amide derivative
represented by the following general formula (I).
##STR00002##
[0017] In addition, according to a second aspect of the present
invention, in the scandium extraction method as described in the
first aspect, the amide derivative is at least any one of a glycine
amide derivative, histidine amide derivative, lysine amide
derivative and aspartic acid amide derivative.
[0018] Furthermore, according to a third aspect of the present
invention, in the scandium extraction method as described in the
first or second aspect, the acidic solution is subjected to the
solvent extraction while adjusting the pH of the acidic solution to
the range of 1 to 4.
[0019] Moreover, according to a fourth aspect of the present
invention, in the scandium extraction method as described in any
one of the first to third aspects, the acidic solution is a
solution formed by mixing sulfuric acid with nickel oxide ore to
leach out nickel.
Effects of the Invention
[0020] According to the present invention, since it is possible to
extract scandium with a high recovery rate even in a low pH range,
calcium and magnesium can be efficiently separated, contrary to
convention extraction agents. In addition, the number of extraction
stages in actual operation is few, and thus the equipment scale can
be condensed; therefore, scandium can be recovered
inexpensively.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows the results when extracting scandium from an
acidic solution containing calcium, magnesium and scandium, using
an extraction agent of an example; and
[0022] FIG. 2 shows the results when extracting scandium from an
acidic solution containing calcium, magnesium and scandium, using
an extraction agent of a comparative example.
PREFERRED MODE FOR CARRYING OUT THE INVENTION
[0023] Although specific embodiments of the present invention will
be explained in detail hereinafter, the present invention is in no
way limited to the following embodiments, and can be implemented by
adding appropriate modifications within the scope of the object of
the present invention.
[0024] The present invention subjects an acidic solution containing
calcium, magnesium and scandium to solvent extraction by way of an
extraction agent consisting of an amide or amide derivative, and
extracts the above-mentioned scandium from the above-mentioned
acidic solution.
Extraction Solvent
[0025] The extraction agent consists of an amide derivative
represented by the following general formula (I).
##STR00003##
[0026] In the formula, substituents R.sup.1 and R.sup.2 indicate
the same or different alkyl groups. The alkyl group may be linear
or branched chains. R.sup.3 indicates a hydrogen atom or an alkyl
group. With the present invention, by introducing an alkyl group to
the backbone of the amide, it is possible to raise the
lipophilicity and use as an extraction agent.
[0027] The above-mentioned amide derivative is at least any one of
a glycine amide derivative, histidine amide derivative, lysine
amide derivative and aspartic acid amide derivative. In the case of
the amide derivative being a glycine amide derivative, the
above-mentioned glycine amide derivative can be synthesized by the
following method. First, 2-halogenated acetyl halide is added to an
alkyl amine of a structure represented by NHR.sup.1R.sup.2 (R.sup.1
and R.sup.2 are the same as the above-mentioned substituents
R.sup.1 and R.sup.2), and a hydrogen atom of amine is substituted
with the 2-halogenated acetyl by way of nucleophilic substitution
reaction, thereby obtaining a 2-halogenated (N,N-di)alkyl
acetamide.
[0028] Next, the above-mentioned 2-halogenated (N,N-di)alkyl
acetamide is added to a glycine or N-alkylglycine derivative, and
one of the hydrogen atoms of the glycine or N-alkylglycine
derivative is substituted with (N,N-di)alkyl acetamide by way of
nucleophilic substitution reaction. The glycine alkyl amide
derivative can be synthesized by these two stages of reaction.
[0029] It should be noted that, if glycine is replaced with
histidine, lysine or aspartic acid, it is possible to synthesize a
histidine amide derivative, lysine amide derivative or aspartic
acid amide derivative.
Extraction of Scandium
[0030] To extract scandium ions using an extraction agent
synthesized by the above-mentioned method, an acidic aqueous
solution containing the target scandium ions is adjusted, while
adding and mixing this acidic aqueous solution to an organic
solution of the above-mentioned extraction agent. It is thereby
possible to selectively extract the target scandium ions in the
organic phase.
[0031] The organic solvent after extracting scandium ions was
isolated, and to this was added a back extraction starting liquid
for which the pH had been adjusted to be lower than the
above-mentioned acidic aqueous solution and stirred, thereby
extracting and separating the target scandium ions from the organic
solvent, and further, the target scandium ions could be recovered
in an aqueous solution by back extracting the target scandium ions
from the organic solvent. As a back extraction solution, for
example, an aqueous solution in which nitric acid, hydrochloric
acid or sulfuric acid is diluted is favorably used. In addition, by
appropriately changing the ratio of organic phase to aqueous phase,
the scandium ions can be concentrated.
[0032] The organic solvent may be any kind so long as being a
solvent in which the extraction agent and metal extracted species
dissolve, and for example, chlorinated solvents such as chloroform
and dichloromethane: aromatic hydrocarbons such as benzene, toluene
and xylene; aliphatic hydrocarbons such as hexane; etc. can be
exemplified. These organic solvents can be used individually, or
two or more organic solvents can be mixed, and alcohols such as
1-octanol can be mixed therewith.
[0033] The concentration of the extraction agent can be set as
appropriate according to the concentration of scandium. In
addition, the stirring time and extraction temperature may be
appropriately set according to the requirements of the acidic
aqueous solution of scandium ions and the organic solution of
extraction agent.
[0034] In order to efficiently recover scandium from an acidic
aqueous solution containing calcium, magnesium and scandium, it is
preferable to add the organic solution of extraction agent while
adjusting the pH of the acidic aqueous solution containing calcium,
magnesium and scandium to at least 1 and no more than 4, and it is
more preferable to add the organic solution of extraction agent
while adjusting the above-mentioned pH to at least 1.5 and no more
than 3.5. Since there is a possibility of not being able to
sufficiently extract scandium if the pH is less than 1, it is not
preferable. Since not only scandium, but also calcium and magnesium
will be extracted if the pH exceeds 4, it is not preferable.
EXAMPLES
[0035] Hereinafter, the present invention will be explained in
further detail by way of the Examples; however, the present
invention is not subjected to any limitations in the following
description.
Example
(Synthesis of D2EHAG)
[0036] As one example of the scandium extraction agent consisting
of an amide or amide derivative, a glycine amide derivative
represented by the following general formula (1), i.e.
N,N-di(2-ethylhexyl)acetamide-2-glycine to which, two 2-ethylhexyl
groups were introduced (N,N-di(2-ethylhexyl)acetamic-2-glycine is
hereinafter referred to as "D2EHAG"), was synthesized.
[0037] The synthesis of D2EHAG was carried out in the following
way. First, as shown in the following reaction formula (II), 2.41 g
of commercially available di(2-ethylhexyl)amine (0.1 mol) and 1.01
g of triethyl amine (0.1 mol) were isolated, dissolved by adding
chloroform to this, then in succession stirred while maintaining at
a temperature in an ice bath, and 13.5 g of 2-chloroacetyl chloride
(0.12 mol) was slowly added by dropping. After adding by dropping
completed, it was stirred for 3 hours at room temperature. After
stirring completed, it was washed once with 1 mol/L hydrochloric
acid, subsequently washed several times with ion exchange water,
and then the chloroform phase was isolated.
[0038] Next, anhydrous sodium sulfate was added in the appropriate
amount (about 10 to 20 g), and after evaporating, was filtered
under reduced pressure, and the solvent was distilled in an
evaporator, thereby obtaining 29.1 g of yellow liquid. The
structure of this yellow liquid (reaction product) was identified
using a nuclear magnetic resonance instrument (NMR), upon which the
above-mentioned yellow liquid was confirmed as being
2-chloro-N,N-di(2-ethylhexyl)acetamide (hereinafter referred to as
"CDEHAA"). It should be noted that the yield of CDEHAA was 85%
relative to di(2-ethylhexyl)amine, which was the source
material.
##STR00004##
[0039] Next, as shown in the below reaction formula (III), while
stirring at room temperature a solution arrived at by adding
methanol to dissolve 8.0 g of sodium hydroxide (0.2 mol), and
further adding 15.01 g of glycine (0.2 mol), 12.72 g of the
above-mentioned CDEHAA (0.04 mol) was slowly added by dropping.
After adding by dropping completed, it was stirred for 15 hours
while maintaining at 60.degree. C. After stirring was finished, the
solvent in the reaction liquid was distilled using an evaporator,
and chloroform was added to the residue to dissolve. After adding
sulfuric acid to this solution to make acidic with a pH of about 1
to 5, it was washed several times with ion exchange water, and the
chloroform was isolated.
[0040] An appropriate amount of anhydrous magnesium sulfate was
added to dehydrate this chloroform phase, and was filtered. The
solvent was removed under reduced pressure again to obtain 12.5 g
of yellow paste. The yield based on the amount of the
above-mentioned CDEHAA was 87%. The structure of the yellow paste
was identified by NMR and elemental analysis, upon which it was
confirmed to be D2EHAG. The extraction agent of the Example was
obtained through the above-mentioned process.
##STR00005##
(Extraction of Scandium)
[0041] Using the above-mentioned extraction agent, extraction
separation of scandium was carried out. The composition of the
source liquid was 4.5 mg/l of scandium, 2.4 mg/l of magnesium and
4.0 mg/l of calcium.
[0042] The above-mentioned source liquid was isolated 3 ml at a
time, a n-dodecane solution containing various types of sulfuric
acid acidic solutions for which the pH was adjusted to 1.0 to 4.0
by adding sulfuric acid to this, and 0.01 mol/L extraction agent in
the same volume (3 ml) as this was added to a test tube, placed
inside a constant temperature storeroom at 25.degree. C. and shaken
for 24 hours. At this time, the pH of the sulfuric acidic solution
was adjusted using ammonium nitrate, ammonia and nitric acid with a
concentration of 1 mol/L.
[0043] After shaking, the aqueous phase was isolated, and the
scandium concentration, calcium concentration and magnesium
concentration were measured using ICP-AES. In addition, the organic
phase was back extracted using 2 mol/L nitric acid. Then, the
scandium concentration, calcium concentration and magnesium
concentration in the back extract phase were measured using
ICP-AES. From these measurement results, the extraction rates of
scandium, calcium and magnesium were obtained, defining in amount
of material in organic phase/(amount of material in organic
phase+amount of material in aqueous phase). These results are shown
in FIG. 1. The horizontal axis in FIG. 1 is the pH of the sulfuric
acid acidic solution, and the vertical axis is the extraction rate
of scandium, calcium or magnesium. In the graph, the diamonds
indicate the extraction rate of scandium, the squares indicate the
extraction rate of calcium, and the triangles indicate the
extraction rate of magnesium.
Comparative Example
(Synthesis of DODGAA)
[0044] N,N-dioctyl-3-oxapentane-1,5-amic acid (hereinafter referred
to as "DODGAA"), which is a conventional, known rare earth metal
extraction agent, was used as the extraction agent of the
Comparative Example.
[0045] The synthesis of DODGAA was carried out as follows. First,
as shown in the below reaction formula (IV), 4.2 g of anhydrous
diglycol acid was taken in a round-bottom flask, and 40 ml of
dichloromethane was placed thereto to make a suspension.
Subsequently, 7 g of dioctylamine (98% purity) was dissolved in 10
ml of dichloromethane, and was slowly added with a dropping funnel.
While stirring at room temperature, anhydrous diglycol acid reacted
and it was confirmed that the solution become transparent, and thus
reaction completed.
##STR00006##
[0046] Next, the above-mentioned solution was washed with water,
and the water-soluble impurities were removed. Then, sodium sulfate
was added as a dehydrating agent to the solution after water
washing. Then, the solution was suction filtered, and subsequently
the solvent was evaporated using an evaporator. Then, after
recrystallized (three times) using hexane, it was vacuum dried. The
recovered amount of the obtained substance was 9.57 g, and the
yield based on the above-mentioned anhydrous diglycol acid was
94.3%. Then, the structure of the obtained substance was identified
by way of NMR and elemental analysis, upon which it was confirmed
to be at least 99% purity DODGAA.
(Extraction of Scandium)
[0047] Scandium was extracted by the same method as the Example,
except for the extraction agent being DODGAA. The results are shown
in FIG. 2. The horizontal axis in FIG. 2 is the pH of the sulfuric
acid acidic solution, and the vertical axis is the extraction rate
of scandium, calcium or magnesium. In the graph, the diamonds
indicate the extraction rate of scandium, the squares indicate the
extraction rate of calcium, and the triangles indicate the
extraction rate of magnesium.
Results
[0048] It has been confirmed that, by using the extraction agent
(D2EHAG) of the Example, scandium could be extracted at a high
extraction rate in a wide pH range, and could consequently be
separated from magnesium and calcium (FIG. 1). On the other hand,
with the extraction agent (DODGAA) of the Comparative Example, if
the pH was not at least 2.5, a scandium extraction rate enough to
satisfy in an industrial sense could not be obtained, and from this
it was confirmed that, not only scandium, but also magnesium and
calcium, which are impurities, were extracted, and separation was
difficult (FIG. 2).
* * * * *